Sponge rubber typewriter key biasing means



July 27,1965 sHIGEAKl KURAMocl-u 3,197,011

SPONGE RUBBER TYPEWRITER KEY BIASING MEANS BY wu,

ATTORNEYS July 27, 1965 sHlGEAKl KURAMocHI 3,197,011

SPONGE RUBBER TYPEWRITER KEY BIASING MEANS Filed March 15, 1963 2 Sheets-Sheet 2 INVENTOR ff//gag//,QA/nacff/ BY ATTORNEYS United States Patent 3,197,011 SPONGE RUBBER TYPEWRITER KEY BIASHG MEANS Shigeaki Kuramochi, Bunkyo-ku, Tokyo, `apan, assigner to Louis Marx & Co., Inc., New York, NX., a corporation of New York Filed Mar. 13, 1963, Ser. No. 264,937 2 Claims. (Cl. 197-17) This invention relates to typewriters and, more particularly, to a novel and improved biasing and cushioning means for the keys of a typewriter.

In the construction of typewriters, means must be provided for biasing the keys to the return or ready position after they have been struck, and it is further desirable to provide cushioning means whereby the action of the keys is rendered easier as well as less noisy in operation. Various means have been proposed and used for effecting these functions, one of the more usual arrangements comprising coil spring means for returning the keys to their ready or at rest position.

In a typewriter, each typing key is part of a lever which is operatively associated with a type bar. The keys are usually mounted for pivotal movement and there is an inter connection between each typing key and its associated type bar whereby, upon depression of a typing key, the associated type bar is struck against paper on the platen of the typewriter. The interconnection between the individual keys and the type bars may be made either directly or through the interposition of intermediate cornponents such as, for example, pivotally mounted bell cranks.

In accordance with the present invention, the use of coil springs and the like for biasing the typing keys to their inactive position is eliminated in a novel, simple and inexpensive manner. More particularly, a metal channel is disposed to extend transversely of the key levers between their operating ends and their pivoted ends, this channel being disposed beneath the typing key levers. Within the channel, there is a rectangular strip of sponge rubber or other resilient cushioning material, which preferably extends normally to a height a little above the upper edges of the channel flanges. Furthermore, the channel flanges are formed with transversely aligned slots, each associated with a particular typing key lever.

When a typing key is depressed, its lever compresses the resilient strip, being guided in its downward movement by the slots in the channel anges and, as the key is released, the resilient strip biases the key back to its inactive position. The arrangement has the advantage that it provides for both pivotal and sliding movements of the keys, such sliding movements being essential in arrangements wherein the typing keys are connected to the type basket by means of intermediate bell cranks or the like.

While by no means limited thereto, the invention is particularly applicable to the typewriter shown and described in the copending application of Willis E. Rexford led March 13, 1963, for Typewriter, Serial No. 264,- 843. Accordingly, in the following description the invention will be described as applied to this particular form of typewriter.

For an understanding of the principles of the invention, reference is made to the following description of a typical embodiment thereof as illustrated in the accompanying drawings. In the drawings:

FIGS. 1 and 2 are longitudinal vertical sectional views through a typewriter incorporating the biasing and cushioning means of the invention, and showing the parts in two different positions;

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FIG. 3 is a vertical longitudinal sectional view of the typewriter, taken in a different plane from that of FIGS. 2 and 3, and illustrating a pivot arrangement for shift levers;

FIG. 4 is a partial plan view of the typewriter, taken on the line 4 4 of FIG. l; and

FIG. 5 is an exploded perspective view illustrating th components of the invention.

In the drawings, only those parts of the typewriter which are actively associated with the biasing and cushioning means of the invention have been illustrated, certain other parts of the typewriter such as the ribbon feed and support, the carriage mechanism, the type basket, and the like being omitted as they are not of any importance in understanding the present invention.

Referring to the drawings, the illustrated typewriter includes a substantially at metal base 2li having a reinforcing rim 2l and supporting feet 22. Adjacent the keyboard, generally indicated at 45, base 20 is formed with a rimmed recess 23. n

A sheet metal bracket 25 is secured to base 20 in any desired manner, as by the use of twisted tongues and slots, welding, brazing, or the like, and bracket 25 is elongated transversely of typewriter base 20 and has arms 26 extending upwardly at each end thereof. Arms 26 are provided with horizontally extending and relatively elongated slots 27, which are transversely aligned with each other, and these slots receive a universal bar or rod 100 which operates appropriate components of the typewriter responsive to depression of a typing key or actuation of a space bar. Bar or rod 100 is anchored in position in any suitable manner, so that its opposite ends extend through slots 27. Each side arm 26 is further formed withan aperture 28 to receive a pivot rod 89 for bell crank levers 75 interconnecting typing keys 70 to the type bars of the type basket. A horizontal ear or shelf 29 is formed at the upper end of each arm 26, and may be used for securing a shell or cover or the like in position.

The keyboard includes a plurality of typing keys in the form oi L-shaped levers having relatively short vertical arms 74 and relatively elongated horizontal arms 73. The keys are arranged in three rows, with the outer row being indicated at 79A, the intermediate row at 70B, and the inner row at 76C, the rows being progressively higher from the outer edge of the typewriter inwardly thereof, as is normal with typewriters. It will thus be noted that the keys are arranged in three groups each having a different length horizontal arm 73.

Each key lever lll has an operating button 76 secured on the upper end of its vertical arm, and these operating buttons, in the usual manner, are imprinted or otherwise provided with indicia indicating which type bar is actuated by which key. For a purpose to be described, the innermost end of each key is reduced as at 77, and keys 70A and 70B are formed with enlargements 73 intermediate the ends of their horizontal arms, as indicated more particularly in FIGS. 1 and 5. The keyboard further includes a space bar 80 supported upon a pair of levers S1 spaced transversely of base 2li and extending longitudinally thereof, these levers being pivoted upon shaft 89 as fully described in said copending application. The inner end of each space bar lever di is provided with a downwardly extending abutment S4, and the space bar levers are biased in a clockwise direction, as viewed in FIGS. l, 2 and 3, by suitable coil springs Ill.

Each typing key 70 is mechanically connected to its associated type bar of the type basket by means of a respective bell crank pivoted on shaft 89. Each bell crank 75 has a normally vertical arm 87 and a normally Patented July 27, 1965 E horizontal arm '88; The outer end of each horizontal arm 8S is provided with a bent tab 79 which extends through an aperture in the associated typing key 70. In the case of keys 70A and 70B, these apertures are located in the area of enlargements 78. In the case of typing keys 70C, the aperture is located at the intersection of the horizontal and vertical arms of the typing key. A wire 113 is pivotally connected to the free end of vertical arm 87 of each bell crank 75, and connects the bell crank to the proper type bar of the type basket. The type basket is supported by means of a yoke having arms 68 pivotally connected to the arms 26 by means of rivets 69.

As fully described in said copending application of Willis E. Rexford, the typewriter is provided with a pair of shift levers 85 each having a pair of heads 86 adjacent its outer end,rone head being adjacent the lowerrnost or outer row of keys and the other head being adjacent the intermediate row of keys. These shifts levers extend rearwardly and their rear ends-are connected to rods 114 by means of which, when a shift key or lever is depressed, the type basket is moved downwardly relative to the carriage assembly so that upper case characters are printed when a typing key 70 is struck.

All of the several levers are guided and maintained in properly spaced relation by a formed sheet metal guide comb illustrated at 90 as having front and rear anges 91 and 96 secured to base 24 of bracket 25, a front wall 92, a top wall 93, and a rear wall 94. This guide comb is formed with front wall slots 95 and rear wall slots 95A, aligned with slots 95, each of which receives a typing lever 70 and its associated bell crank 75. The horizontal arm of each bell crank extends through a front wall slot 95, and the verticalv arm of eachbell crank extends upwardly through a slot 95 in the top Wall 93, the slots 95 in the front and top walls being continuations of each other. Guide comb 90 further has a pair of relatively wide slots 98 in its front wall 92, each of which receives, in addition to a typing key 70 and its associated bell crank 75, one of the levers 81 for space bar 80. As described in said copending application, each lever 81 has an upwardly extending projection extending through a slot in the top Wall of the comb 90 for cooperation with universal rod or bar 100. Shift' key levers V85 are guided in open ended slots 99 in front wall 92 of comb 90.

Rearwardly of comb 90, Ithere is a rear guide 101 for typing key 1evers`70 and shift levers 85. Rear guide 101 is an angular sheet metal member having a base secured to main support base 20 in any suitable manner, and a vertical wall formed with closed Vend slots 103 each receiving reduced end 77 of a typing key lever 70. The rear or vertical wall of member 101 is also formed, adjacent each end, with an upwardly opening slot 104 serving to guide a shift key lever 85. Shift key levers 85 are further guided by angular tabs 102 each disposed immediately outside a shift key lever k85.

In accordance with the invention, novel means are provided for cushioning and biasing typing key levers 70. This means is generally indicated at 105,'and comprises a metal channel 106 extending transversely of base 20 beneath theV longer and generally horizontal arms 73 of the typing key levers. The flanges of this channel are formed with upwardly opening slots 107, each in guiding relation with a respective horizontal arm 73 of a typing key lever 70. A strip 108 of sponge rubber or other resilient cushioning material, which is substantially rectangular in cross section, is disposed within metal channel 106 and terminates, at each end, lshort of a shift key lever 85. Each typing key lever 70 has its horizontal portion 73 bearing against the upper surface of sponge rubber strip` 108 and, due to the confinement of this sponge rubber strip between the flanges and the base of channel 106, the strip is so constrained that it exerts an upward force against each key 70 thereby biasing this key to its inactive or upper position.

As a key 70 is struck, its horizontal portion 73 slightly compresses cushion 108 as its reduced inner end 77 bears against the upper end of the associated slot in rear guide 101, and key lever arm portion 73 may move horizontally as well as pivotally, to accommodate the pivotal movement of the associated bell crank 75. When thekey is released, the compressed portion of rubber strip 108 re-expands to bias the depressed key back to its upper portion.

FIG. 1 illustrates thetyping keys in their normally inactive position, wherein it will be noted that each key rests on the upper surface of rubber strip 108 and upwardly at a small angle. y As each key is depressed, as indicated in FIG. 2, horizontal portion 73 thereof compresses a portion of rubber strip 108 las the key is moved downwardly by pressure on its button 76. This swings associated bell crank lever 75 about pivot shaft 89 and, as a result of such swinging movement, lever 70 moves rearwardly a slight extent, sliding over rubber strip 108. As each key is released,` the re-expansion of rubber strip 108 moves the key back to the position shown in FIG. l.

The combination of channel 106 with rubber strip 108 therein provides a novel cushioning and biasing means for the typing keys, eliminating the necessity of providing coil spring or tensionfspring means for maintaining the keys in their upper or inactive positon. The arrangement is simple, inexpensive, and easy to mount into the typewriter by securing to base 20 in yany desired manner. In the particular embodiment shown, such securing is facilitated by the fiat base 20 engaging the base of channel 106.

As a further feature of the invention, just in advance of cushioning and biasing means a pair of tabs 109` are struck up from the base 20, each having a height such that its upper end is a substantial distance above the upper edges of channel 106. These up-struck tabs 109 act as pivot bearings for shift lever keys 85.

It may be noted, as an incidental feature, that the length of the horizontal arm of each bell crank lever 75 is in inverse ratio to the length of the horizontal arm 73 of its associated typing key 70, as best illustrated in FIG. 5. This provides for easier and more uniform operation of the typing keys during typing.

While a specific embodiment of the invention has been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.

What is claimed is:

1. In a typewriter, a plurality of typing key levers arranged beside each other at a predetermined normal elevation and adapted, when used, to be depressed downwardly from said normal elevation thereof, an elongated rigid channel extending beneath and located adjacent said levers, said channel having a bottom wall distant from said levers and a pair of side walls extending upwardly toward said levers and said channel having an open top, said side walls of said channel being formed with notches extending downwardly from upper edges of said side walls and aligned with said levers, an elongated body of resilient compressible springy material located in and lling said channel and having an upper face engaging said levers when the latter are at their normal elevation, said levers when depressed below their normal elevation compressing said body into said channel with said bottom and side walls of said channel confining said body so that when a depressed lever is released said body will spring back to its initial configuration and will return a depressed lever to its normal elevation so that said body in combination with said channel acts as a spring-return for said levers, an elongated guide extending parallel to said channel at oneside thereof and formed with a plurality of slots through which said levers respectively extend, said levers having upper edges in engagement with upper ends of said slots, respectively, so that said guide at said upper ends of said slots acts as a fulcrum for said levers, an elongated shaft located on the side of said channel opposite from said guide and also extending parallel to said channel, a plurality of second levers pivotally carried by said shaft and having distant from said shaft free ends which are pivotally connected to said key levers so that when the latter are depressed said second levers will turn about said shaft while said key levers will move longitudinally along said body of resilient material while being depressed downwardly from and returning to their normal elevation.

2. In a typewriter as recited in claim 1, said second levers extending from said shaft away from said channel so that the pivotal connections between said second levers and said key levers are more distant from said channel than said shaft.

References Cited by the Examiner UNITED STATES PATENTS Gaveau 197--33 X Steiner 197--17 Walberg 84-467 Thompson 197-17 LaRue et al. 267-1 Zinke 267--1 Frechette 1197-17 Templeton et al 197-17 ROBERT E. PULFREY, Primary Examiner.

EUGENE R. CAPOZIO, Examiner. 

1. IN A TYPEWRITER, A PLURALITY OF TYPING KEY LEVERS ARRANGED BESIDE EACH OTHER AT A PREDETERMINED NORMAL ELEVATION AND ADAPTED, WHEN USED, TO BE DEPRESSED DOWNWARDLY FROM SAID NORMAL ELEVATION THEREOF, AN ELONGATED RIGID CHANNEL EXTENDING BENEATH AND LOCATED ADJACENT SAID LEVERS, SAID CHANNEL HAVING A BOTTOM WALL DISTANT FROM SAID LEVERS AND A PAIR OF SIDE WALLS EXTENDING UPWARDLY TOWARD SAID LEVERS AND SAID CHANNEL HAVING AN OPEN TOP, SAID SIDE WALLS OF SAID CHANNEL BEING FORMED WITH NOTCHES EXTENDING DOWNWARDLY FROM UPPER EDGES OF SAID SIDE WALLS AND ALIGNED WITH SAID LEVERS, AN ELONGATED BODY OF RESILIENT COMPRESSIBLE SPRINGY MATERIAL LOCATED IN AND FILLING SAID CHANNEL AND HAVING AN UPPER FACE ENGAGING SAID LEVERS WHEN THE LATTER ARE AT THEIR NORMAL ELEVATION, SAID LEVERS WHEN DEPRESSED BELOW THEIR NORMAL ELEVATION COMPRESSING SAID BODY INTO SAID CHANNEL WITH SAID BOTTOM AND SIDE WALLS OF SAID CHANNEL CONFINING SAID BODY SO THAT WHEN A DEPRESSED LEVER IS RELEASED SAID BODY WILL SPRING BACK TO ITS INITIAL CONFIGURATION AND WILL RETURN A DEPRESSED LEVER TO ITS NORMAL ELEVATION SO THAT SAID BODY IN COMBINATION WITH SAID CHANNEL ACTS AS A PRING-RETURN FOR SAID LEVERS, AN ELONGATED GUIDE EXTENDING PARALLEL TO SAID CHANNEL AT ONE SIDE THEREOF AND FORMED WITH A PLURALITY OF SLOTS THROUGH WHICH SAID LEVERS RESPECTIVELY EXTEND, SAID LEVERS HAVING UPPER EDGES IN ENGAGEMENT WITH UPPER ENDS OF SAID SLOTS, RESPECTIVELY, SO THAT SAID GUIDE AT SAID UPPER ENDS OF SAID SLOTS ACTS AS A FULCRUM FOR SAID LEVERS, AN ELONGATED SHAFT LOCATED ON THE SIDE OF SAID CHANNEL OPPOSITE FROM SAID GUIDE AND ALSO EXTENDING PARALLEL TO SAID CHANNEL, A PLURALITY OF SECOND LEVERS PIVOTALLY CARRIED BY SAID SHAFT AND HAVING DISTANT FROM SAID SHAFT FREE ENDS WHICH ARE PIVOTALLY CONNECTED TO SAID KEY LEVERS SO THAT WHEN THE LATTER ARE DEPRESSED SAID SECOND LEVERS WILL TURN ABOUT SAID SHAFT WHILE SAID KEY LEVERS WILL MOVE LONGITUDINAL ALONG SAID BODY OF RESILIENT MATERIAL WHILE BEING DEPRESSED DOWNWARDLY FROM AND RETURNING TO THEIR NORMAL ELEVATION. 